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The
process of making pure white lead pigment has ancient origins.
One of the first methods was called the “Dutch Process” and was
developed in the 17th century. The first step in this process
was for workers to take the dull, bluish gray, metallic lead to
the smelter to be recast in the shape of large thin belt
buckles. The lead buckles were then corroded with acid in the
presence of carbon dioxide. Next, these lead buckles were
stacked inside ceramic pots that contained a few ounces of
diluted acetic acid, usually vinegar. The stack room was filled
with layers of spent, tanbark filled pots, and boards until the
stack almost touched the ceiling. After 6-14 weeks, the chemical
reaction was complete and the blue bed was transformed
into a white bed. Often times the white lead encrusting
the buckles grew so thick it would crack the ceramic pots.
The
workers would then disassemble the white beds by dumping the
ceramic pots onto separating tables, hand scrapping and pounding
the flaky lead carbonate from the buckles. Some factories used
mechanical separators operated by workers to perform this task.
After this process, the powder was dried and put into wooden
caskets for shipment. White lead pigment was then added to
linseed oil, other pigments, and turpentine to create lead-based
paint.
The
formation and usage of lead pigments were known over a century
ago to cause serious illness and in some cases death among
workers and the public. Workers became ill in all steps of the
manufacturing process and in the application of the paint. Many
suffered from painter’s colic, better known as plumbism, which
is a toxic condition produced by the absorption of excessive
lead into the system. Often workers were sent to the hospital
for lead poisoning within the first month of employment.
In
1910, the House of Representatives committee conducted a hearing
for a bill that may have kept lead-based paint off American
walls. At this hearing Marion E. Rhodes testified that, “the
most eminent scientists and doctors of Great Britain…reached the
conclusion that white lead is poison…the small particles that
result from chalking…when taken by inhalation into the lungs,
are absorbed and become poison to the system.” A separate bill
was introduced to the house in May 1910 which, in the interest
of public health, called for federal intervention in regulating
the manufacture, sale, and use of any paint containing white
lead. This bill also included a measure to require all
lead-based paints to be “labeled with a skull and crossbones and
the words Poison: white lead.” These warnings went
unheeded.
The
president of the National Lead Company, Edward J. Cornish,
admitted in a 1921 letter to the dean of Harvard Medical School,
David Edsall, that “manufacturers as a result of fifty to sixty
years experience, agreed that lead is a poison when it enters
the stomach of man—whether it comes directly from the ores and
mines and smelting works or from the ordinary forms of carbonate
of lead, lead oxides, and sulfate and sulfide of lead”.
Not
only had the paint manufacturers identified and admitted the
dangerous nature of lead, the international community had as
well. At the 1921 Third International Labor Conference of the
League of Nations held in Geneva, 400 delegates from 40 nations
discussed the regulation of the lead trade. The United States
did not attend the Conference and did not agree to the
resolution to ban lead-based paints from homes. It was not until
1977 that the federal government prohibited the use of lead
paint from most residential applications. From 1910 through
1977, over 4,000 tons of lead pigments were used in homes and
products throughout the United States.
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